Elastic tread for boots and shoes.



P. W. PRATT.

ELASTIC TREAD FOB. BOOTS AND SHOES.

APPLICATION FILED JAN. 26, 1906. nnmzwnn MAR. 13, 1909.

a 9 36, 8 1 O. T l I Patented Oct. 12, 1909.

q v-i/cmeooea Y K 2 OC \7 W4 M UniTEnsTATEs PATENT OFFlCE.

PHILIP w. PRATT, oriaos'ron, massaonusn'r'rsnssmnoa 'ro CHARLES r. BROWN,

TRUSTEE, or READING, mnssacnusnrrs.

ELASTIC TREAT) FOR BOOTS 4ND SHOES.

Specification of Letters Patent.

Patented Oct. 12, 1909.

Application filed January 26, 1906, Serial No. 297,965. Renewed March 13, 1909. Serial No. 483,295.

T all whom 'it may concern:

Be it known that I, PHILIP W. PRATT, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new 5 and useful Improvements in Elastic Treads for Boots and Shoes, of which; the following is a specification.

This invention relates to treads for boot and shoe heels and soles, comprising a body portion of rubber, and a non-slipping plug or plugs embedded in the rubber body and forming a part of the tread surface, which presents greater frictional resistance to slipping movement. of the tread on the surfaces with whichit comes in contact than is presented by the rubber of which the body is composed.

The invention consists in an elastic tread comprising a body portion of rubber, which includes the marginal portions of the treadpiece, and one or more plugs com )osed of a mixture of rubber and cork re need to small fragments embedded in the rubber, the corkfragments being held by the rubber of the plug, the margin of the plug being formed by a ring of textile material, as hereinafter described; One face of the plug is exposed, and forms a part of the tread surface, said face being substantially flush with or projecting slightly beyond the tread face of the all-rubber body. The plug is inserted in the body, so that its margin is covered by the material of the body, the cork fragments in the margin of the plug being thus confined by the surrounding portion of the all-rubber body, and prevented from dropping out or being dislodged. The tread thus formed differs from a tread the entire body of which is composed of a mix- 40 ture of rubber and cork fragments, in that the margin of thetread is homogeneous, and does not present cork fragments. The said margin is therefore of uniform color, and its continuity is not liable to be interrupted by the removal of. cork fragments, as would be the case if the entire body were composed of amixture of rubber and cork. vMoreover, the all-rubber margimbesides being of uniform color, is capable of being trimmed to )0 conform to the shape of the leather heel or soleto which the elastic tread is applied;.

whereas, a margin composed in part of cork fragments cannot be thus trimmed, without dislodging some of the cork fragments and giving the trimmed margin a pitted surface.

Of the accompanying drawings, forming a part ofthis specification, Figure lrepresents a side-view of an elastic heel-tread emseotion on line 22 of Fig. 1.

The same, reference characters indicate the same parts in both figures.

In the drawings,a represents an elastic trwd-pieoeor body, which is composed of rubber or of a composition of which rubber is an ingredient, said composition being houniform.

1 represents aplug composed of a mixture of rubber and cork-fragments, the latter being embedded in the rubber and confined by it. The plug is inserted in the body a, one side of the plug being exposed as a part of the tread surface, while the margin and the other side are, covered by the homogeneous material of the body. The cork fragments on the margin'of the plug are thus confined, and prevented from dropping out, while, the cork-fragments on the tread-face are as a rule heldzin "place byv the pressure of, the tread face against the ground,'pavement, or floor. The plug 1) is surrounded by a ring 0 composed of convolutions of duck or other textile fabric, the object of the ring being to present a n'orrslipping annular tread surface. The cork fragments do not extend to the margin of the body a, hence said margin presents the usual appearance of an all-rubber tread, and is adapted to be trimmedand finished in the usual manner. The ring 0 has greater wear-resistance qualities than the center part composed of rubber and cork. Therefore the plug, instead of wearing away at 7 its margin and acquiring a crownmg shape, will become slightly dished by wear,

and is therefore lessliable to slip.

The tread'piece on its side opposite to that'in which the plug is embedded, is recessed, and provided with a number of discontinuous pyramidal or conical projections.

(Z rising from the bottom of the recess and sion of the tread are diminished at the porbodying my invention. Fig. 2 represents a mogeneous, in that its texture and colo r are terminating flush with the surface of the 'ized,

,fabric'coated with unvu tion where the pensates for the additional stifiness given by the less yielding plug, so that the tread ody is of uniform softness and resilience throughout.

The lug b and body a are molded before the rub er .contained in said parts is vulcanand they are united by vulcanization after they are assembled, this being the ordinary method of uniting a wear-resisting plug to a rubber body; Heretofore a tread of this character has been made by assembling a plug made by coilin a strip of textile canized rubber, and an unvulcanized rubber body, and then permanently uniting said parts by vulcanization, as shown, for example, in Letters Patent of the United'States No- 769,324. I In a tread having a coiled fabric tread, the rubber ingredient 'of the tread at the upper or inner end of the tread is limited to the narrow lines 5 between the "convolutions of the fabric. Hence, there is a limited union between the rubber ingredient of the tread and the rubber of the body. 'Mytread b on the other hand presents a much greater proportion of rubber at its inner end, the continuity of the rubber beinginterrupted onl surface particles or. pieces of cor I am enabled therefore to secure a firmer union plug is located. This oom- I by the between. the inner end of the plu and the body by vulcanization than heretoore The i ring a of textile material, forming the margin of the plug, offers more resistance to wear than the rubber and cork portion of the plug and the surrounding rubber body of the plug. Hence the Wear to which the tread surface of the heel is subjected, causes the textile ring a to form an annular ridge, I projecting slightly from the tread surface, and increasing the frictional hold of said surface on the pavement or ground, thus re.- ducing the liability of slippage.

I claim:

E An elastic tread composed of a homof geneous elastic body and a plug composed of a mixture of rubber and cork forming the i center of the plug, and a ring of textile material surrounding the said center, and forming the margin of the plug, the said plug I being inserted in the elastic bod with its 1 margin covered by the material 0 the body, 2 the said parts being united by vulcanization. i In testimony whereof I have afiixed my signature, in presence of two witnesses.

PHILIP W. PRATT.

Witnesses: I G. F. BROWN,

E. BATCHELDER. 

